Governing apparatus



Sept. 9, 1941. F. SCHMIDT 2,255,439

' GOVERNING APPARATUS Filed Oct. 10, 1940 3 Sheets-Sheet 1 INVENTORWITNESSES:

HENR F -S-cHMmT. $6 4410 2' BY I h. R1 43,

ATTORNEY S pt. 9, 1941.

H. 'F SCHMIDT GOVERNING APPARATUS Filed Oct 10, 1940 s Sheets-Sheet 2 InIn mama m M. o H M T C E v (M W fl 0 NF v m. a M 7 0- N J E n m Milli 0omm 00 5 B E A Q 2 l. .8 0 A k k or w 7/ J ,Q, I' L hI 1 ,7 w fit 41 mamm o z y 4 7 2& A a m m w x A v mm m u mm 43 am .8 m 3 5 x m 3 M m .m

p 1941- H. F. SCHMIDT 3 GOVERNING APPARATUS Filed Oct. 10, 1940 3Sheets-Sheet 3 Wli'NESSES: I I I INVENTOR ENRY E SCHMIDT v BY BM/5, g

ATTORNEY ingproduced thereby. In accordance with the Patented Sept. 9',1941 Henry F. Schmidt, 'Lansdowne, Pa., assignor to WestinghouseElectric & Manufacturing Company, East Pittsburgh, Pa.,-

Pennsylvania a corporation of Application October 10, 1940, Serial No.360,549

. 18 Claims.

This invention relates to hydraulic governing mechanism for controllingthe admission of motive fluid to prime movers and. it has for an Obj'ect to provide apparatus of this character wherein the regulating orcontrolling pressure, in ad- I dition to controlling the position of theservomotor pilot valve, also serves to secure operation of the operatingpiston without the latter operation introducing fluctuations in theimpeller pressure suflicient to impair the speed responsive efiect ofthe latter.

Heretofore, impellers developing liquid pressure and varyingsubstantially as the square of the prime mover speed have been used toprovide a controlling or regulating pressure for the servomotoroperating the motive fluid admission valve.

f Ordinarily such controlling or regulating pressure is used to controlthe position of the servomotor pilot valve and the operating piston ismoved by a separate source of motive fluid, movement of the operating.piston by liquid under' pressure developed by theimpeller beingobjectionable on account of. pressure fluctuations bepresent invention,movement of the operating Fig. 3 shows a third embodiment similar inmany respects to that of Fig. 2; and,

Fig. 4 shows a fourth embodiment.

Referring to Fig. 1, there is shown a centrifugal impel1er,'at l0,driven from the prime mover-or turbine, at H, and furnishing controllingand motivating liquid for the servo-motor, at I2, which operates theadmission valve l3. An important feature of the present invention is toprovide for operation of the s'er vo motor by motive liquid supplied bythe impeller without impairing the emcacy of the impeller pressure toexert a pulsation-free speed-responsive controlling effect on theservo-motor.

The impeller, at II], is of the type commonly used for governingpurposes and it comprises a runner l4 and a casing 15.

v The casing provides a pressure'space l6 bounding the runnerand asuction space ll atone end'of the latter, the easing having an eye I81axially aligned 'with the runner and opening into the suction space.

A suction conduit I9 provides for passage of liquid from the reservoir20 through the eye to piston is secured by the application of fluidpressure derived from the impeller without introducbeing effected by theuse of aconstant- -flow valve in the line supplying liquid from theimpeller to the operating piston, the operating piston and its cylinderincorporating an accumulatorproviding, at least, for admission valve'closing movements which do not depend upon therate at which liquid issupplied to the operating cylinder.

A further object'of the invention is to provide ing such fluctuations orpulsations, this result servo-motor apparatus of the above characterwherein the fluid draining therefrom is supplied to the impeller so asto improve the suction. lift of the latter.

A further object of the invention is to pro- .vide apparatus of theabove character wherein the liquid used is lubricating oil and drainagefrom the operating cylinder is provided at a sumcient pressure forbearing lubrication.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith this application, in which: i v

Fig. 1 a diagrammatic and sectional view showing one form of theimproved apparatus:

' g. 2 is a view similar to Fig. 1 but showing a second embodiment;

the accompanying drawings, forming a part of the' suction space. 1Preferably, as is common practice with hydraulic governing apparatus,the inlet end of the suction conduit I 9 is formed with a mixing orcombining cone or chamber 2| into which liquid furnished from thechamber I6 is discharged at high velocity from the jet 22.

.The servo-motor, at 12, comprises suitable housing structure 23providing the operating cylinder 'and pilot valve bores 24 and 25 withinwhich are disposed the operating piston 26 and the pilot valve 21,respectively.

The operating piston 26 is connected by a linkage, at 28, 'to theadmission valve l3, and by a follow-up linkage, at 30, to the pilotvalve 21.

The linkage, at 28, may comprise an operating.

piston rod 32, a..link 33, a lever 34, and a valve rod pivotallyconnectedtogether and the lever having a fulcrum 36; and the linkage, at30, may

include the piston rod 32, the link 33, a fulcrumed leverfl, a link 38,and a compression spring 39 engaging the piston valve 21.

The structure 23 has passages 40 and 4| communicating with the operatingcylinder bore 24 at either side of the operating piston 26 andcommunicating with the pilot valve bore through suitably located ports42'and 43.. The pilot valve 2] has spaced enlargements 44 and 45defining,- with the bore 25, aconnecting space or chamber 45-for theports 42 and 43, and the enlargement 44 being arranged to cover more orless the port .42.

The pilot valve 21 has a piston face 41 at its lower end cooperatingwith the closed lower end of the pilot valve bore 25 to form thepressure chamber 48 connected by a conduit 49 to the impeller pressurespace l6. Also, the upper end of the pilot valve bore 25v is preferablyconnected by a drain conduit to the reservoir 20.

The operating piston 26 divides the operating cylinder bore 24 into anexpansible and contractible chamber or space 52 thereabove and a drainchamber or space 53 therebelow and forming a part of the drain space,the passages 40 and 4| communicating, respectively, with the chambers'52and 53. The drain chamber 53 is connected to the drain conduit 54, alsoforming a part of the drain space and the operation of which will bemore fully hereinafter set forth.

The constant flow valve, at 56, supplies liquid to the expansible andcontractible chamber 52 conduit 55 and having'one or more lanternopenings or ports 59 communicating with the space 60 at the downstreamside of the second or variable orifices and communicating with theexpansible and contractible chamber 52. A tubular member 6| isslida-ble'in the enlargement, the

forward portion thereof being formed to pro-. vide the fixed orifice '62and the rearward end portion 63 thereof functioning as a slide valve tocover the opening or openings 59 to a variable extent in orderto-provide the second or variable orifice. A spring 64 exerts its forceon the tubular member in a direction tending to uncover the lanternopening or openings 59 and thereby to increase the flow area of thesecond orifice, the force of the spring being opposed by that of thedifferential of liquid pressure across the fixed orifice 62 and actingon the. annular piston-area provided by the forward end of the tubularmem-' ber 6|. The spring force is varied by adjustment means 51 actingtherebelow, and the pilot valve 21 would occupy a position with thefluid and spring forces acting thereon in equilibrium, the portion 44 ofthe pilot valve covering the port 42 sufliciently to maintain therequired pressure in the chamber 52 such that the outflow of liquidtherefrom through the passage 40 will be equal to theinflow of liquidthereto which is constant from the passage 55. If the load shoulddecrease, the speed and impeller pressure would increase, therebyupsetting the equilibrium condition of the pilot valve 21 and causingthe latter to move upwardly, decreasing the restriction of the port 42to provide for thesame;rate or discharge with a reduced pressure in theexpansible and contractible chamber 52, the reduced pressure thereinpermits the then preponderating force of the spring means 51 to causethe operating piston 26 to move the motive fluid admission valve memberIS in a closing direction. In addition to the increased force ofcompression of the spring 29' brought about by upward movement ofthepilot valve 21. in response to increase in impeller pressure, theforce of compression of the spring would further be increasedconcurrently with movement of the operating piston due to operation ofthe follow-up linkage, at 36, and movement of the operating piston 26wouldcontinue until the equilibrium condition is again restored with theopening of the admission valve restricted suitably for the decrease inload.

If the load should increase, both the speed and impeller pressure woulddecrease, thereby upsetting the equilibrium of forces acting on thepilot valve 21,'the preponderating spring force moving the latterdownwardly to further restrict the port 42, in consequence of whichthepressure would build up in theexpansible and contractible chamber 52and the operating piston would, on that account, be moved against thespring 51 to move the valve member IS in an opening direction. Theseoperations would continue until an equilibrium condition is attainedwith the admission valve adjusted to proportion drain space, ispreferably arranged to improve ch rge into the latter.

of thefollower 65. If the pressure at the down-' a stream side of thesecond or variable orifice should change, this would induce apressurechange inthe spacebetween the orifices, thereby upsetting thedifferential across the first orifice,

' and the tubular member would move in such a direction as to give acompensating effect so as to maintain fiow through the two orificessubstantially constant, irrespective of pressure variations at thedownstream side'ofthe second or variable orifice.

. With the expansible and contractible chamber 52 of the operatingcylinder supplied with liquid from the impeller through the conduit 55and its constant flow valve, at 56, it will be apparent .that, withsuitable operation of the pilot valve 21, the capacityexists forproviding the necessary change in pressure in the expansible andcontractible chamber 52 to provide for proper valve operation. Normally,'for a given load, the piston 26 would occupy an equilibrium positionwith the force of fiuid pressure acting there-.

above in equilibrium with the force of the spring the suction effect ofthe impeller. Accordingly, it is formed so that its discharge end 66 isaxially a nedwith the impeller and the eye for dis- Furthermore, wherethe liquid is lubricating oil, the drain conduit may be modified toprovide a pressure source for bearing lubrication, in which event, asshown in Fig, 1, the drain conduit 54 would have first and secondbranches 61 and 66, the branch 61 having a spring loaded relief valve 69and the discharge end 66 and the branch 66 leading to the bearingshaving a constant flow valve, at 16, similar to that already described.

The spring loaded relief valve operates to maintain a desired pressureat the upstream side thereof and-ahead ofthe constant flow valve, at 10,and the, latter operates to provide for constant flow with themaintenance of substantially constant pressure upstream thereof,irrespective of the downstream side thereof.

In Fig. 2, the expansible chamber or space, instead ofbeingprovidedentirely within the operating cylinder bone, as in Fig. 1,is provided partly therein, as shown at 52a, and partly, as shown at52b, in a separate structure, at 12. In this view, the operatingcylinder bore is divided into .sage 40a.

the expansible and contractible space or chamments 'of the admissionvalve independently of her 52a and the drain space or chamber 53a, andpassages 40a and a join such spaces with the interior of 'the pistonvalve bore 250, the piston valve 21a having apiston enlargement acooperating with the port end 42a of the'pasoperation with the bore 25a,provide a space for.

has an upper enlargement 45a,

connecting the ports 42a and 43a so that liquid may be transferred fromthe chamber 52a to the chamber 53a. In addition, the pilot valve I 21ahas a lower enlargement 13, which, with the from the latter, liquid isconducted by the conduit 55b to the space 14.

The structure, at 12, provides a bore 16 within" which is disposed apiston 11, the latter dividing the bore into the expansible chamber 52band the drain chamber 531}. A spring 18 in the chamber 53b exerts forceon'the piston 11 in opposition to the force of fluid pressure appliedthereto. The piston 11 has an opening 19 with which cooperates'the plug80 depending from and adjustably carried by the top 8| of the structure,at 12, the plug having a lower tapered end 82 so thatdownward movementof the piston may be limited, the piston moving down wardly until theescape of liquid through the opening 19 is equal to that supplied to thechamber 52b by the constant flow valve, at 56a. By

adjusting the plug 80, the maximum volume of balanced by theupwardly-acting'spring force of I the chamber 52bv may be varied, itscapacity preferably being at least about three-quarters of that of theoperating cylinder. Y

In Fig. 2, impeller. pressure is supplied to the upper end of the pilotvalve bore 25a by the conduit 49a, the drain conduit 51a being connectedto the lower end of the bore.

Comparing Figs. 1 and 2, it will the operations of transferring liquidfrom the contractible and expansible spaces or chambers- 52 and 52a tothe drain spaces or chambers 53 be seen that the rate atwhich motiveliquid is supplied from the impeller. In this view, the accumulatorfeaturesqare providedin the operating-cylinder.

,The'operating cylinder bore 24b of Fig. 4 is divided by the pistons 2 band Ila intoexpansible'and contractible chambers 52c and 52d and thedrain chamber 53c.

The piston "a has an opening 190 with which cooperates a plug 80acarried by theupper piston 26b. The spring means 51a is arranged betweenthe pistons 26b and 11a 'andaspring 84 bears against the upper face ofthe piston 26h,

The'impeller pressure c nduit SSchas a constantv flow. valve, at 56b,discharging into the chamber 52d and the latter is connected, by thepassage 55d, to'the piston valve space a, the piston valve constructionbeing similar to that of Fig. 2, that is, with increase in impellerpressure due to decrease in load, the piston valve spaceltb' places thepassages 40b and Mb in communication so that liquid may discharge fromthe chamber 520 into-the chamber 53c,

and, upon upward movement of. the piston valve, in consequence ofincrease in load, the. piston valve space 14o places thepassage 55d incommunication with the passage 40!) to supply liquid from theaccumulator space or chamber 52d to the chamber 520. I i

In order, that the operation of the construction shownin Fig. 4 may bebetter understood,'consideration should be given to the forcesacting onthe composite piston arrangement constituted by the pistons 26b and Ha.Normally, the pistons would occupy an equilibrium position, the force offluid pressure and the force of the spring 84 acting downwardly on thepiston 26!) being thespring means 51a, and the force of the latterspring means acting downwardly on the piston 'Hawould be balanced by theupwardly-acting fluid pressureforce applied to the latter. Should theload decrease, the impeller pressure would increase, causingestablishment of communication of the passages 40b and Mb to provide fortransfer of liquid from the chamber 520 to the chamber 530; and, withthese passages in communication and as the vforce of the spring means,

51a is greater than'that of the spring 84, the piston 261) would bemoved upwardly to cause 17h]; admission valve to move in auclosingdireci310 and 53a to secure rapid contraction of the contractible andexpansible'chambers are the same.

On the other hand, the expanding movements. of these chambers aredifferent. In Fig.1, the

rate at which the chamber 52 is-expanded de pends upon the rate ofinflow and the extent of escape.

. Such upwardmovem'ent of the piston 26b a rate depending upon inflowfrom the constant flow valve 56b, the parts finally coming to rest InvFig. 2, opening of the admission valve is much more rapid for the reasonthat.

the supply of liquid accumulated in the charm ber 52b is available fortransfer to the space 5241 to secure rapid expansion of the latter withdownward movement thereof and movement of the admission valve in anopening directionv when the conduit 55b is placed in communication withthe port 42a by the piston valve nection with Fig, 1.

Fig. 4 is fundamentally similar to Fig. 2 in that accumulator .andliquid transfer features provide for rapid opening and closing movewithrestriction of the admission valve suitable I for thereduced load andwith the various forces acting on the piston valve 21b and on thepistons 7' 26b and 'l'la-in balance. If the load should increase, thepiston valve. 21b would move upwardly,

.placing the space 14a in communication with the port 42b, wherebyliquid may flow rapidly from the chamber 52d to .thechamber v52c to movethe operating piston 26b downwardly to open the admission valve wider,the flow of liquid for'ithis purpose dependingupon the relativelygreater; force of the spring means 51a as compared'to that of the spring84. While this operation involvesthe piston: 1111 moving downwardlyrelatively to the upper piston 26b, as the chamber 52d. is continuouslysupplied with liquid by the l constant flow'valvaat 56b, it will berestored to correct relative position. .The pistons 26b and l la'continue-to move with opening of the admission valve until the latter isopened sufliciently for the increase in load and equilibrium of the'various forces acting on the piston valve 21b and on the pistons 26band "a are restored. Movement of the operating piston transmitted by thefollow-up linkage changes the spring force acting on the pilot valveuntil, such force is in balance with the impeller pressure force actingthereon and with the pilot valve in its neutral ornormal position. Also,liquid is supplied from the constant flow valve, at 561), until'thelower constant-flow device utilizing fluid delivered by the impellerunder regulating pressure to provide motive fluid for the operatingmember of the servo-motor.

4. The combination with a prime mover having an admission valve, of aservo-motor including an operating member connected to the admissionpiston 11a is restored to its-normal position relatively to the upperpiston 26b, movement of the lower-piston ceasing with forces actingthereon in balance andwith inflow of liquid to the charm ber52d equal-tooutflow therefrom. In this connection, it will be noted that theaccumulator capacity of the chamber SM is limited by the plug 80acooperating with the opening 19a of the piston 1121; the piston movingupwardly until discharge through the opening 19a is equal to that ofsupply through the constant flow. valve From the foregoing, it will-beapparent that there is provided a servo-motor whose operating piston ismoved by liquid furnished from the impeller without impairing theeficacy. of the latter to provide speed-responsive or controllingpressure on the pilot valve.

While the invention has been shown in several forms it will be obvioustothose skilled in the art that it is notso limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and it is desired, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appendedclaims.

What is claimed is; v l 1. In a hydraulic governing systemfor a prime'mover having a controlling element, means providing fluid underpressure varying as a function,

valve and a pressure-responsive pilot valve controlling the'applicationof inelastic motive fluid to the operating member, an impeller driven bythe prime mover and providing inelastic fluid under regulating pressurevarying as a function of the speed of the latter, means for applyingfluid under regulating pressure to the pressureresponsive pilot valve,means including a con-- stant-flow device utilizing fluid underregulating pressure to' provide motive fluid for the operating member ofthe servo-motor, and means utilizing fluid exhausted from theservo-motor to improve the suction lift of the impeller.

5. In hydraulic governing apparatus, an impeller including a runner anda casing, an operating cylinder, an operating piston in the cylmder,-means providing motive liquid for the operating cylinder including aconduit connected to the impeller casing, means providing for constantflow through the conduit from the impeller, means for securing operationof the operating piston in the operating cylinderand including apressure-responsive pilot valvecontrolling the application of motiveliquid to the latter, and means including a conduit connected to theimpeller casing for applying impeller pressure to thepressure-responsive pilot valve.

6. In hydraulic governing apparatus, an impeller for developing oilunder pressure and including a runner and a casing, an operatingcylinder, an'operating piston in the cylinder,

of the prime mover speed and including a centrifugal impeller driven bythe prime mover, hydraulic operating mechanism for the controllingelement, means responsive to pressure pro vided by the impeller forcontrolling said mechanism, and means including a constant-flow devicefor supplying fluid from the impeller for motivation of the hydraulicoperating mechanism.

2. The combination with a prime mover having an admission valve, of amotor device including an operating movable member connected to theadmission valve and pressureresponsive means for controlling theapplication of inelastic motive fluid to the operating member to securemove-' ment thereof, means operated by the prime means providing motiveoil for the operating cylinder including a first conduit connected tothe impeller casing, means providing for constant flow through theconduit from the impeller, means for securing operation of the operatingi piston in the operating cylinder and including a mover to provideinelastic fluid under regulating pressure varying as a function of thespeed of the prime mover,- means for applying fluid under regulatingpressure to the pressure-responsive means, and means including aconstant flow device utilizing fluid under regulating pressure toprovide motivating fluid for the operating 'viding for constant flowfrom the impeller pressure-responsive-pilot valve controlling theapplication of motive oil to the latter, means iricluding a secondconduit connected to the im-= peller casing for applying oil underimpeller pressure to the pressure-responsive pilot valve, .athlrdconduit for oil discharging from the servo-motor, a constant flow valvein the third conduit, and means including a relief valve for maintaininga substantiall constant r ahead of the constant flow vilve. p esure 7.In hydraulic governing apparatus, an impeller including a runner and acasing, said casing having an eye aligned axially with the runner, a'suction conduit communicating with Y the eye, an operating cylinder, anoperating pis-' ton in the cylinder, means providing motive liquid forthe operating cylinder including a conduit connected to the impellercasing, means prothrough the conduit, means for securing operation ofthe operating piston in the operating cylinder and including apressure-responsive pilot valve controllingapplication of motive liquidto the latter, means including a conduit connected to the impellercasing for applying impeller pressure to the pressure-responsive pilotvalve, means including a conduit for liquid exhausted from the operatingcylinder, said last-named conduit comprising first and second branches,a valve inthe first branch for maintaining a constant pressure aheadthereof and providing for flow'therethrough of liquid in excess ofthat-required for the pressure, said first branch having its dischargeend communicating with the suction conduitand aligned with the impellereye, and means providing for constant flow through the second.

branch.

8. In hydraulic governing apparatus, an impeller including a runner anda casing providing a pressure space, an operating cylinder, an operatingpiston in the cylinder, a first conduit for supplying liquid from theimpeller pressure space to the space of said operating cylinder at oneside of the operating piston, a constant flow valve in said conduit,spring means exerting force on the other side of the operating piston, apilot valve for controlling the discharge of liquid from the space atthe first side of the operating piston, means for controlling the pilotvalve including a necting the latter .with said first chamber and withsaid drain space; a pilot valve movable in said pilot valv'e chamber tocontrol communication-of said passages; means including apressure-responsive device for moving the pilot valve; a device forproducing pressure of liquid varying as a function of speed andhaving apressure space; means including a first conduit for connecting saidpressure space with said contractible pressure-responsive device, and asecond conduit connecting the impeller pressure space with thepressure-responsivedevice.

9. In hydraulic governing apparatus, an impeller including a runner. anda casing providing pressure and suction spaces, a suction conduit forthesuctionspace, an operating cylinder, an operating piston in thecylinder, a second conduit for, supplying liquid from the impellerpressure space to the space of said operating cylinder at one side ofthe'operating piston, a constant flow.

valve in said conduit, spring means exerting force on the other side ofthe operating piston, a pilot valve for controlling the flow of liquidfrom. the space at the first side of the operating piston to the spaceat the otherside thereof,-

means for controlling'the pilot valve including a pressure-responsivedevice, a third conduit connecting the impeller pressure space with thepressure-responsive device, and a drainage conduit communicating withthe space of the operatingcylinder at said other side of the operatingpiston and having its discharge end communicating with the suctionconduit and directed toward the suction space of the impeller in orderto improve the suction lift of the latter.

10. In hydraulic governing apparatus, an impeller including a runner anda casing providing a pressure space, an operating'cylinder, an operatingpiston in the cylinder, a firstconduit and expansible chamber; aconstant-flow valve in said first conduit; and a second conduit forconnecting said pressure space with said presviding a piston valve boreand first, second and third passages connecting the latter with thedrain space,'the first expansible and contracti-ble space, and thesecond expansible and contractible space, "respectively; a piston valvein said bore and movable to place said second passage in communicationeither with the first passage or with 'the third passage and tointerrupt such v communication; said piston valve having a pistonfaceicooperating with the bore to provide apressure chamber; means forthrottling escape of liquid from said second expansible and contractiblespace to the drain space such that, with expansion of' the second spacebeyond a prede-, termined point, the resistance to escape is verysubstantially reduced; a device for producing pressure of liquid varyingas a function of speed and having pressure and suction spaces; secondconduit; a first linkage connecting said first pisfor supplying liquidfrom the impeller'pressure Y space to the space of said operatingcylinder at one side of the operating piston, a constant flow valve insaid conduit, spring means exerting force on the other side of theoperating piston, a pilot valve for controlling the fiow of liquid fromthe space at the first side of the operating piston to the space at saidother side thereof, means for controlling the pilot valve including apressure-responsive device, a second conduit connecting the impellerpressure space with the pressure-responsive device, a drainage conduitcommunicating with the space of the operating opposes that of liquidpressure applied to the pis-.

and third conduits forconnecting said pressure space with said secondcontractibleand expansible space and with'said pressure chamber, re-

spectively; a constant-flow valve in the second ton with the admissionvalve; a second linkage connecting the first piston with the pistonvalve and including a spring so disposed that its force ton valve pistonface. 5

13.- The combination with a prime mover having an admission valve, of anoperating cylinder, an operating piston in the 'cylinder and connectedto the admission valve, biasing means acting on the operating piston tomove the admission valve in a closing direction, anaccumulator,meansoperated by the prime mover to provide liquid under regulatingpressure varying cylinder at said other side of the operating pis ton, aconstant fiow valve in the drainage conduit, and means including arelief valve for P maintaining a substantially constantpressure in f thedrainage conduit ahead of the constant fiow valve.

v 11. In hydraulic apparatus for controlling the position of a primemover motive fluid admission valve, means providing a drain space; meansincluding an operating piston defining an expansible and contractiblechamber; spring means exerting its force on the operating piston in adirection to contract said chamber; means providing a pilot valvechamber and passages conas a function of the speed of the latter, a con-,dui't for delivering liquid from the last-named means to theaccumulator, means providing for constant fiow through the conduit,means providing a pilot valve bore, a first passage connecting the pilotvalve bore to the operating cylinder to supply liquid to the latter toact onthe operating piston against the force of the biasing means tomove the admission valve in an opening directioma second passageconnected to the bore and providing a part of the drainage space, athird passage connecting the accumulator and the bore,a pilot valvemovable in the bore to connect said first passage either with the secondpassage or with the third passage, means including pressure-responsivemeans for moving the pilot valve, and a conduit for supplying liquidunder regulating pressure from said regulating pressure developing meansto the pressure-responsive means.

14. The combination with a prime mover having an admission valve, of anoperating cylinder, an operating piston in the cylinder and connected tothe admission valve, biasing means acting on the operating piston tomove the admission valve ln a closing direction, an accumulator, meansoperatedby the prime mover to provide liquid under regulating pressurevarying as I a function of the speed of the latter, aconduit fordelivering liquid from the last-named means to the accumulator, meansproviding for constant flow through the conduit, means providing a pilotvalve bore, a first'passage connecting the pilot valve bore to theoperating cylinder to supply fluid to the latter to act on the operatingpiston against the force of the biasing means to move the admissionvalve in an opening direction, a second passage connected to the boreand providing a part of the-drainage space, a third passage connectingthe accumulator and the bore, a pilot valve movable in the bore toconnect said first passage either with the second passage or with thethird passage, pressure-responsive means for the pilot valve comprisedby a piston face formed on the latter and a portion of the bore, aconduit for supplying liquid under regulating pressure from saidregulating pressuredeveloping means to the pressure-responsive means,means providing for escape of liquid from the accumulator so that liquidmay accumulate therein to a predetermined volumetric extent, andfollow-up means connecting the operating piston and the pilot valve.

15. The combination with a prime mover having an admission valve; of anoperating cylinder; an operating piston in the cylinder and connected tothe admission valve; biasing means exerting force on the operatingpiston to move the admission valve in a closing direction; saidoperating piston separating the interior of the operating cylinder intoa liquid pressure space and a drain space portion with the liquidpressure space so arranged that, 'with the admission of liquid underpressure thereto, the force thereof acts on the operating piston to movethe latter against the force of the biasing means to move the admissionvalve in an opening direction; an accumulator cylinder; an accumulatorpiston in the accumulator cylinder and cooperating with the latter toprovide an accumulator liquid pressure space; biasing means acting onthe accumulator piston to contract said accumulator liquid pressurespace; an impeller operated by the prime mover to provide liquid underpressure varying as a function of the speed of the latter, said impellerincluding a casing cooperating with a runner to provide a liquidpressure space; a conduit for delivering liquid from the impellerpressure space to the accumulator pressure space; aconstant-flow valvein said conduit; means providing a pilot valve bore; a first passageconnecting the pilot valve bore to the operating cylinder pressurespace; a second passage connecting the bore and the drain space portionresponsive means for the pilot' valve comprised by a piston face formedon the latter and a portion of the bore; a conduit for supplying liquidfrom the impeller pressure space to the pressure-responsive means; meansproviding for escape of liquid from the accumulator pressure space sothat a predetermined volume of liquid'may acposition of a prime movermotive fluid admisof the operating cylinder; a third passage connectingthe bore and the accumulator pressure sion valve, means providing adrain space; means including an operating piston defining an expansibleand contractible chamber spring means exerting its force on theoperating piston in a direction to contract said chamber; 'meansproviding a pilot valves-bore and passages connecting the bore withsaid-chamber and with said drain space; a pilot valve-movable in saidbore to control communication of said passages; said pilot valve havinga piston face cooperating with said bore to provide a pressure chamber;a de-' vice for producing pressure of liquid varying as a'function ofspeed and having a pressure space;

means including a first conduit for connecting said pressure space withsaid contractible and expansible chamber; a constant flow valve in saidfirst conduit; a second conduit for connecting said pressure space withsaid pressure chamber; a first linkage connecting the operating pistonand the admission valve; and a second linkage connecting the operatingpiston and the pilot valve and including a spring so disposed that itsforce opposes that of liquid pressure applied to the pilot valve pistonface,

17. In hydraulic apparatus for controlling the position of a prime movermotive fluid admission valve, means including a first conduit providinga drain space; means including an operating piston defining anexpansible and contractible chamber; spring means exerting its force onthe operating piston in a direction to contract said chamber; meansproviding a pilot valve bore and-passages connecting the latter withsaid chamber and with said drain space; a pilot valve movable in saidbore to control communication of said passages; said pilot valve havinga pistonv face cooperating with said bore to provide a pressure chamber;a device for producing pressure of liquid varying as a function of speedand including an impeller and a casing therefor; said casing definingsuction and pressure spaces and having an eye axially aligned with theimpeller and opening into the suction space; means including a secondconduit for connecting said pressure space with said contractible andexpansible chamber; a constant flow valve in said second conduit; athird conduit for connecting said pressure space with said pressurechamber; a suction conduit connected to the eye of the impeller casing;said first conduit having its discharge end opening into the suctionconduit and directed axially toward the eye of the impeller casing so asto assist the suction lift of the impeller; a first linkage connectingthe operating piston and the admission valve; and a second linkageconnecting the operating piston and the pilot valve and including aspring so disposed that its force opposes that of liquid pressureapplied to the pilot valve piston face.

18. In hydraulic apparatus for controlling the position of a prime movermotive fluid admission valve, means. including a first conduit providinga drain space; means including an operating piston defining anexpansible and contractible chamber; spring 'means exerting its force onthe operating piston in a direction to contract said chamber; meansproviding a pilot valve bore and passages connecting the bore with saidchamber and with said drain space; a pilot valve movable in said bore tocontrol communication of said passages; said pilot valve having a.piston face cooperating with said bore to provide a pressure chamber; adevice for producing pressure of liquid varying as a function of speedand having flow valve in said second conduit; a third conduit forconnecting said pressure space with said pressure charhber; a firstlinkage connecting the operating piston and the admission valve: a

apressure space; means including a second conduit for connecting saidpressure space with said contractible and expansible chamber; a constantsecond linkage connecting the-operating piston and the pilot valve andincluding a spring so disposed-that its force opposes that of liquidpressure applied to the pilot valve piston facef a through oi liquid inexcess of. that required for the pressure. a

'HENRY' F.

